harakit/src/scrut.c

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/*
* Copyright (c) 20232024 DTB <trinity@trinity.moe>
* Copyright (c) 2024 Emma Tebibyte <emma@tebibyte.media>
* SPDX-License-Identifier: AGPL-3.0-or-later
*
* This program is free software: you can redistribute it and/or modify it under
* the terms of the GNU Affero General Public License as published by the Free
* Software Foundation, either version 3 of the License, or (at your option) any
* later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
* details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see https://www.gnu.org/licenses/.
*/
#include <assert.h> /* assert(3) */
#include <stdio.h> /* fprintf(3), stderr, NULL */
#include <stdlib.h> /* EXIT_FAILURE, EXIT_SUCCESS */
#include <string.h> /* memset(3), strchr(3) */
#include <sysexits.h> /* EX_OSERR, EX_USAGE */
#include <unistd.h> /* access(3), getopt(3), pledge(2), unveil(2), F_OK, R_OK,
* W_OK, X_OK */
#include <sys/stat.h> /* lstat(3), stat struct, S_ISBLK, S_ISCHR, S_ISDIR,
* S_ISFIFO, S_ISGID, S_ISREG, S_ISLNK, S_ISSOCK,
* S_ISUID, S_ISVTX */
char *program_name = "scrut";
#define OPTS "bcdefgkprsuwxLS"
/* this is an array so main:sel's size can be known at compile time */
static char opts[] = OPTS;
static int
usage(char *argv0) {
(void)fprintf(stderr, "Usage: %s [-" OPTS "] file...\n", argv0);
return EX_USAGE;
}
int main(int argc, char *argv[]) {
char sel[(sizeof opts) / (sizeof *opts)];
program_name = argv[0] == NULL ? program_name : argv[0];
#ifdef __OpenBSD__
if (pledge("rpath stdio unveil", NULL) == -1) {
perror(program_name);
return EX_OSERR;
}
#endif
if (argc < 2) { return usage(program_name); }
{ /* option parsing */
char *p;
memset(sel, '\0', sizeof sel);
for (int c; (c = getopt(argc, argv, opts)) != -1;) {
if ((p = strchr(opts, c)) == NULL) { return usage(argv[0]); }
else {
assert(p - opts < sizeof sel / sizeof *sel); /* bounds check */
sel[p - opts] = c;
}
}
/* straighten out selections; permute out nulls */
p = sel;
for (size_t i = 0; i < (sizeof sel) / (sizeof *sel); ++i) {
if (sel[i] != '\0') {
*p = sel[i];
if (&sel[i] != p++) { sel[i] = '\0'; }
}
}
}
if (optind == argc) { return usage(argv[0]); }
for (argv += optind ; *argv != NULL; argv = &argv[1]) {
struct stat buf;
#ifdef __OpenBSD__
if (unveil(*argv, "r") == -1) {
perror(program_name);
return EX_OSERR;
}
#endif
if(access(*argv, F_OK) != 0 || lstat(*argv, &buf) == -1) {
return EXIT_FAILURE; /* doesn't exist or isn't stattable */
}
for (size_t i = 0; sel[i] != '\0'; ++i) {
if (
(sel[i] == 'b' && !S_ISBLK(buf.st_mode))
|| (sel[i] == 'c' && !S_ISCHR(buf.st_mode))
|| (sel[i] == 'd' && !S_ISDIR(buf.st_mode))
|| (sel[i] == 'e' && 0)
|| (sel[i] == 'f' && !S_ISREG(buf.st_mode))
|| (sel[i] == 'g' && !(buf.st_mode & S_ISGID))
|| (sel[i] == 'k' && !(buf.st_mode & S_ISVTX))
|| (sel[i] == 'p' && !S_ISFIFO(buf.st_mode))
|| (sel[i] == 'r' && access(*argv, R_OK) != 0)
|| (sel[i] == 'u' && !(buf.st_mode & S_ISUID))
|| (sel[i] == 'w' && access(*argv, W_OK) != 0)
|| (sel[i] == 'x' && access(*argv, X_OK) != 0)
|| (sel[i] == 'L' && !S_ISLNK(buf.st_mode))
|| (sel[i] == 'S' && !S_ISSOCK(buf.st_mode))
) { return EXIT_FAILURE; }
}
}
return EXIT_SUCCESS;
}